Former Vice President Dick Cheney is having elective back surgery at George Washington University Hospital.

Cheney spokeswoman Lucy Tutwiler says the surgery Thursday is to deal with lumbar spinal stenosis, a common cause of lower back pain in older adults.

Spinal stenosis is a narrowing of the spinal canal -- the passage for the spinal cord -- which in turn puts pressure on nerves, causing pain. Surgery is done to widen the passage and ease that pressure, typically by removing a bit of the vertebra.

Dr. Anthony Caputy, chairman of the hospital's neurosurgery department, is performing the operation.

Cheney is 68 years old. He has had four heart attacks.